Mmmm. Pepperoni, mushroom and definitely cheese. But I don't say no to seafood or vegetable, if it's well done. I know lots of people don't like anchovies, but I think they're good with some mixtures - not pepperoni however.
I have friends whose selection of toppings seemed to be unique in their town. (I forget exactly what it was, didn't seem exceptional to me.) But when she'd phone in the order, without getting any identifying details, they'd say, "Good evening, Mrs Moore."